An assessment of the masked message hypothesis: Sea urchin egg messenger ribonucleoprotein complexes are efficient templates for in vitro protein synthesis☆

[摘要] Therateofproteinsynthesisinunfertilizedseaurchineggsisverylow,althoughallcomponentsforproteinsynthesisarepresent.TodeterminewhethereggmessengerRNAsareunavailablefortranslationbecauseof“masking”byphenol-solubleinhibitors,crudeandpurifiednonpolyribosomalmessengerribonucleoproteincomplexes(mRNPs)fromeggsofStrongylocentrotuspurpuratusweretranslatedinvitroinawheatgermcell-freesystem.CrudeandpurifiedeggmRNPswerenearlyastranslatableasthemRNAsextractedfromthemRNPs,suggestingthatthemRNPswerenotmasked.NodifferenceintherelativetranslationalactivitiesofmRNPsandtheirconstituentmRNAswasrevealedbyisolatingthemRNPsinbuffersofdifferentionicstrengthorinthepresenceofproteaseandribonucleaseinhibitors.Furthermore,kineticanalysisoftheinvitrotranslationandtranslationofthemRNPsandmRNAsatseveralconcentrationsofK+,Mg2+,andtemplateallindicatethatmRNPsareefficienttemplatesfordirectingproteinsynthesis.SeparationonpolyacrylamidegelsoftheproductsofinvitroandinvivotranslationdemonstratedthatbothmRNPsandmRNAsextractedfromthemRNPssynthesizedinvitrohigh-molecular-weightpolypeptides,someofwhichwerealsosynthesizedinvivo.AlthoughseaurchineggmRNPsmaynotbemasked,thereareseveralalternativemechanismsforregulatingtranslationintheegg.

[学科分类] 生物科学（综合）